1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to wireless communication, and more particularly, to a technology for determining channels to be used in a wireless network.
2. Description of the Related Art
In recent years, as a wireless network becomes more common, transmission of a large capacity of multimedia data has been increasingly required. As a result, research on an effective data transmission method in a wireless network environment has been required. Further, wireless transmission of high quality video, such as DVD (Digital Video Disk) video, HDTV (High Definition Television) video, and the like, among various home appliances has been increasingly required.
One task group of IEEE 802.15.3c is trying to promote a technology standard for transmitting a large capacity of data by a wireless home network. In this technology standard that is referred to as a so-called mmWave (Millimeter Wave), in order to transmit a large capacity of data, a wave (that is, electric wave having a frequency in a range of 30 to 300 GHz) is used in which a physical wavelength is represented in millimeters. In general, this frequency band has been limited for use in communication operators, electric wave astronomical observations, or vehicle collision prevention.
In an IEEE 802.11b specification or an IEEE 802.11g specification, a carrier wave frequency is 2.4 GHz, and a channel bandwidth is approximately 20 MHz. Further, in an IEEE 802.11a specification or an IEEE 802.11n specification, a carrier wave frequency is 5 GHz, and a channel bandwidth is approximately 20 MHz. Meanwhile, the mmWave uses a carrier wave frequency of 60 GHz, and has a channel bandwidth in a range of approximately 0.5 to 2.5 GHz. Accordingly, it may be understood that the mmWave has a larger carrier wave frequency and channel bandwidth than the standard that exist in the IEEE 802.11 series. As such, when using a high frequency signal (mmWave) having a wavelength measured as a unit of millimeter, a very high transmission rate measured as a unit of several Gbps may be achieved. Further, a size of an antenna may be reduced to 1.5 mm or less and thus it is possible to implement a single chip including the antenna.
In recent times, research has been made for transmitting uncompressed audio or video data (hereinafter, simply referred to as uncompressed AV data) using a high bandwidth of the mmWave. The AV data is lossy compressed by a method of removing portions that are not sensitive to the human, visual and auditory senses by motion compensation, a DCT conversion, quantization, variable length coding, and the like. Accordingly, there are disadvantages in the compressed AV data in that image quality deterioration may occur in the compressed AV data due to the compression loss, and AV data compression and restoring processes between a transmitting device and a receiving device should be based on the same standard. Meanwhile, there are advantages in the uncompressed AV data in that the uncompressed AV data includes digital values (for example, R, C, and B components) indicating pixel components, and thus may provide a high definition image quality.
However, data, such as a beacon, an ACK packet, a MAC command packet, and the like, which has a small amount of information, is transmitted through a channel using a wide bandwidth, which causes wireless resources to be wasted. Therefore, it is necessary to use a channel (low-rate channel) having a narrow bandwidth for transmitting data having a small amount of information and a channel (high-rate channel) having a wide bandwidth for transmitting data having a large amount of information for one wireless network. In this case, a technology is required for appropriately selecting the low-rate channel and the high-rate channel.